Adhesive and semiconductor devices

ABSTRACT

An adhesive composition for bonding of semiconductor chips to their chip mounting component comprising a curable polymer composition that comprises a spherical filler having an average particle size from greater than 100 to 1,000 μm and an aspect ratio of 1 to 1.5. Semiconductor devices according to this invention are characterized in that a semiconductor chip therein is bonded to the mounting component for said chip by the aforementioned adhesive.

BACKGROUND OF INVENTION

This invention relates to an adhesive for bonding semiconductor chips totheir attachment members (hereinafter referred to as the chip mountingcomponent) and to semiconductor devices in which a semiconductor chiptherein is bonded to its chip mounting component by said adhesive. Moreparticularly, this invention relates to an adhesive that can bond asemiconductor chip to its chip mounting component across a constant gapof adequate size and that can provide a thorough relaxation of themechanical stresses acting on said chip. The invention additionallyrelates to highly reliable semiconductor devices.

Within the sphere of adhesives for bonding semiconductor chips to theirchip mounting components, Japanese Laid Open (Kokai or Unexamined)Patent Application Number Hei 7-14859 (14,859/1995) teaches an adhesivethat characteristically contains at least 5 weight % insulating powderconsisting of at least 1 selection from inorganic insulators such asglasses, metal nitrides, and metal oxides that have a particle size of50 to 100 μm. Japanese Laid Open (Kokai or Unexamined) PatentApplication Number Hei 7-292343 (292,343/1995) teaches an adhesivecomprising a platinum compound, spherical organic or inorganic fillerhaving a particle size of 10 to 100 μm and a major axis-to-minor axisratio (hereinafter referred to as the aspect ratio) of 1.0 to 1.5, anorganosilicon compound containing silicon-bonded alkoxy,organopolysiloxane containing at least 2 silicon-bonded hydrogen in eachmolecule, and organopolysiloxane containing at least 2 silicon-bondedalkenyl in each molecule.

The adhesives taught in Japanese Laid Open (Kokai or Unexamined) PatentApplication Numbers Hei 7-14859 and Hei 7-292343, however, haveproblems. It is quite difficult with these adhesives to obtain a largegap or space between the semiconductor chip and its chip mountingcomponent and the size of the gap ends up being nonuniform even when alarge gap can be generated. These adhesives are also unable tothoroughly relax the mechanical stresses acting on the semiconductorchip.

The inventors achieved the present invention as a result of intensiveinvestigations into the problems described above. In specific terms, anobject of this invention is to provide an adhesive that can bond asemiconductor chip to its chip mounting component across a uniform gapof adequate size and that can thoroughly relax the mechanical stressesacting on the semiconductor chip. Another object of this invention is toprovide highly reliable semiconductor devices.

SUMMARY OF INVENTION

The present invention is an adhesive composition intended for thebonding of semiconductor chips to their chip mounting components andcomprises a curable polymer composition that contains spherical fillerthat has an average particle size from greater than 100 to 1,000 μm andan aspect ratio of 1 to 1.5. Semiconductor devices according to thisinvention are characterized in that a semiconductor chip therein isbonded to the mounting component for said chip by the aforementionedadhesive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 contains the cross section of an integrated circuit that is anexample of a semiconductor device according to the present invention.

FIG. 2 contains the cross section of an integrated circuit that is alsoan example of a semiconductor device according to the present invention.Reference Numbers used in the drawings:

1 semiconductor chip

2 semiconductor chip mounting component

3 adhesive

4 conductor

5 lead

6 sealant/adhesive

7 solder ball

8 frame

9 bump

DESCRIPTION OF INVENTION

The adhesive of this invention is intended for the bonding ofsemiconductor chips to their chip mounting components and comprises acurable polymer composition that contains spherical filler that has anaverage particle size from greater than 100 to 1,000 μm and an aspectratio of 1 to 1.5. Semiconductor devices according to this invention arecharacterized in that a semiconductor chip therein is bonded to themounting component The adhesive of this invention will be described indetail first. The spherical filler in this adhesive is the crucialcomponent for achieving bonding between the semiconductor chip and itschip mounting component across a constant gap of adequate size. Theaverage particle size of this spherical silica should be between greaterthan 100 and 1,000 μm (excluding 100 μm). The basis for this range is asfollows. The production of a large gap between the semiconductor chipand its mounting component is highly problematic in the case of adhesivethat uses spherical silica with an average particle size of 100 μm orless. Moreover, even when a large gap can be produced with such anadhesive, the gap will exhibit a tendency toward non-uniformity. At theother extreme, adhesive that uses spherical filler with an averageparticle size exceeding 1,000 μm produces a semiconductorchip-to-mounting component gap that is larger than necessary. The aspectratio of the spherical filler under consideration should be within therange from 1 to 1.5 and is preferably from 1.0 to 1.1. It becomesincreasingly difficult to generate a uniform chip-to-mounting componentgap in the case of adhesive that uses spherical filler whose aspectratio exceeds the given upper limit. In a particularly preferredembodiment, the standard deviation on the particle size distribution ofthe spherical filler does not exceed 10% of the average particle size ofsaid filler.

The spherical filler under consideration is exemplified by inorganicspherical fillers composed of silica, glass, alumina, aluminosilicate,silicon nitride, boron nitride, silicon carbide, carbon, titanium oxide,aluminum, alumite, copper, silver, and stainless steel, and by organicspherical fillers composed of carbon, fluororesin, silicone resin,silicone rubber, epoxy resin, polyimide resin, polyphenylene sulfideresin, and polyetherketone resin. The spherical filler can be hollow orcan be porous with pores on the surface and/or in the interior.Inorganic spherical fillers are preferred.

In a preferred embodiment of the invention, the spherical fillercomprises 1 weight-ppm (part per million) to 5 weight % of the curablepolymer composition. The preferred range is 1 weight-ppm to 2 weight %and the particularly preferred range is 1 weight-ppm to 1 weight %. Itbecomes increasingly difficult to obtain a constant chip-to-mountingcomponent gap when the spherical filler content in the adhesive fallsbelow the above-specified lower limit. At the other extreme, aninability to thoroughly relax the mechanical stresses acting on thesemiconductor chip becomes increasingly prominent when theabove-specified upper limit is exceeded. In addition, in a preferredembodiment, the spherical filler is present in the adhesive in an amountthat avoids a stacking or superposition of neighboring spherical fillerparticles one above the other in the space between the semiconductorchip and its mounting component. For example, the spherical filler ispreferably present in an amount such that the spherical filler particlecount per the coated area is at least 3 and no more than {coatedarea/(particle size of the spherical filler)²}×0.9. When the sphericalfiller content in the adhesive provides a spherical filler particlecount per the coated area of less than 3, or more than {coatedarea/(particle size of the spherical filler)²}×0.9 particles of thespherical filler in which case the particles will overlap each other,and it will become increasingly difficult to obtain a uniform gapbetween the semiconductor chip and its mounting component.

The curable polymer composition used in the present adhesive compositionis exemplified by curable epoxy resin compositions, curable siliconecompositions, curable acrylic resin compositions, and curable polyimideresin compositions. The curable epoxy resin compositions are exemplifiedby curable epoxy resin compositions and curable silicone-modified epoxyresin compositions; the curable silicone compositions are exemplified bycurable silicone compositions, curable epoxy-modified siliconecompositions, curable acrylic-modified silicone compositions, andcurable polyimide-modified silicone compositions; the curable acrylicresin compositions are exemplified by curable acrylic resin compositionsand curable silicone-modified acrylic resin compositions; and thecurable polyimide resin compositions are exemplified by curablepolyimide resin compositions and curable silicone-modified polyimideresin compositions. Curable epoxy resin compositions and curablesilicone compositions are preferred. In a particularly preferredembodiment, the curable polymer composition is a curable siliconecomposition due to the ability of curable silicone compositions tothoroughly relax the mechanical stresses acting on semiconductor chipsand also due to the excellent heat resistance of curable siliconecompositions. The curable silicone compositions are exemplified by thosecurable by condensation reactions, those curable by addition reaction,those curable by ultraviolet radiation, and those curable byorganoperoxide-mediated radical reactions, with additionreaction-curable silicone compositions being preferred. Said additionreaction-curable silicone compositions can comprise, for example, (A)organopolysiloxane having at least 2 alkenyl groups in each molecule,(B) organopolysiloxane having at least 2 silicon-bonded hydrogen atomsin each molecule, (C) an organosilicon compound having Si-bonded alkoxy,and (D) a platinum catalyst.

The organopolysiloxane (A), which is the base component in such anaddition reaction-curable silicone composition, must contain at least 2alkenyl groups in each molecule. This alkenyl is exemplified by vinyl,allyl, butenyl, pentenyl, hexenyl, and heptenyl with vinyl beingpreferred. The non-alkenyl silicon-bonded groups in (A) are exemplifiedby monovalent hydrocarbon groups excluding alkenyl, for example, alkylgroups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, andoctyl; aryl groups such as phenyl, tolyl, and xylyl; aralkyl groups suchas benzyl and phenethyl; and halogenated alkyl groups such as3-chloropropyl and 3,3,3-trifluoropropyl. Methyl and phenyl arepreferred for the non-alkenyl silicon-bonded groups. The proportion ofphenyl in the total silicon-bonded organic groups in (A) is preferablyin the range of from 1 to 30 mole % because this affords a compositionwith excellent cold resistance. Component (A) can be, for example, asingle polymer having a straight-chain, partially branchedstraight-chain, branched-chain, cyclic, or resin-like molecularstructure or can be a mixture of polymers with such molecularstructures. Component (A) preferably has a viscosity (25° C.) in therange from 10 to 1,000,000 mpa·n s.

The organopolysiloxane (B) is a crosslinker for the composition underconsideration and must contain at least 2 silicon-bonded hydrogen atomsin each molecule. The silicon-bonded groups in (B) other than hydrogenare exemplified by monovalent hydrocarbon groups, for example, alkylgroups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, andoctyl; aryl groups such as phenyl, tolyl, and xylyl; aralkyl groups suchas benzyl and phenethyl; and halogenated alkyl groups such as3-chloropropyl and 3,3,3-trifluoropropyl. Methyl and phenyl arepreferred for the non-hydrogen silicon-bonded groups. Component (B) canbe, for example, a single polymer having a straight-chain, partiallybranched straight-chain, branched-chain, cyclic, or resin-like molecularstructure or can be a mixture of polymers. Component (B) preferably hasa viscosity (25° C.) in the range of from 1 to 10,000 mPa·s.

The present adhesive composition preferably contains component (B) in anamount that provides from 0.3 to 10 moles silicon-bonded hydrogen from(B) per mole alkenyl in (A). The composition will not undergo asatisfactory cure when the addition of component (B) provides lesssilicon-bonded hydrogen per mole alkenyl in (A) than the lower limit ofthe given range. When the addition of (B) provides more silicon-bondedhydrogen per mole alkenyl in (A) than the upper limit of the givenrange, the cured product will have diminished mechanical strength.

The organosilicon compound (C) functions to improve the adherence of thecomposition under consideration and must contain at least Isilicon-bonded alkoxy group in the molecule and preferably contains atleast 3 silicon-bonded alkoxy groups in the molecule. The alkoxy in (C)can be, for example, methoxy, ethoxy, propoxy, or butoxy with methoxybeing preferred. The other silicon-bonded groups in (C) are exemplifiedby the hydrogen atom; the hydroxyl group; functional organic groups suchas 3-glycidoxypropyl, 2-(3,4-epoxycyclohexyl)ethyl, and3-methacryloxypropyl; and monovalent hydrocarbon groups, for example,alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl,heptyl, and octyl; alkenyl groups such as vinyl, allyl, butenyl,pentenyl, and hexenyl; aryl groups such as phenyl, tolyl, and xylyl;aralkyl groups such as benzyl and phenethyl; and halogenated alkylgroups such as 3-chloropropyl and 3,3,3-trifluoropropyl. Component (C)preferably contains the vinyl group, silicon-bonded hydrogen, or anepoxy-functional organic group such as 3-glycidoxypropyl or2-(3,4-epoxycyclohexyl)ethyl.

Component (C) is exemplified by 3-glycidoxypropyltrimethoxysilane;3-glycidoxypropyltriethoxysilane;2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; vinyltrimethoxysilane;organosiloxane oligomer whose molecule contains silicon-bonded alkoxy,SiH, and 3-glycidoxypropyl or 2-(3,4-epoxycyclohexyl)ethyl; andorganosiloxane oligomer whose molecule contains silicon-bonded alkoxy,silicon-bonded alkenyl, and 3-glycidoxypropyl or2-(3,4-epoxycyclohexyl)ethyl.

The composition under consideration preferably contains from 0 to 20weight parts component (C) per 100 weight parts component (A). Acomposition containing component (C) in excess of the upper limit of thegiven range will cure to give a cured product with diminished mechanicalstrength.

The platinum catalyst (D) is a catalyst for inducing the additionreaction-mediated cure of the present composition. Component (D) can beexemplified by platinum black, platinum supported on silica micropowder,platinum supported on active carbon, platinum supported on aluminapowder, chloroplatinic acid, alcohol solutions of chloroplatinic acid,olefin complexes of platinum, alkenylsiloxane complexes of platinum,carbonyl complexes of platinum, and thermoplastic resin powder with anaverage particle size of 10 μm or less that contains one or more of thepreviously listed platinum catalysts. The thermoplastic resin in thelast-named example can be, for example, polystyrene resin, nylon resin,polycarbonate resin, and silicone resin.

Component (D) should be added to the present composition in sufficientquantity to induce the cure of the composition. In specific terms,component (D) is preferably added to the composition in an amount thatprovides from 1 to 1,000 weight-ppm platinum metal.

The present composition preferably contains an addition-reactioninhibitor as an optional component. This addition-reaction inhibitor canbe exemplified by alkyne alcohols such as 3-methyl-1-butyn-3-ol,3,5-dimethyl-1-hexyn-3-ol, and 3-phenyl-1-butyn-3-ol; ene-yne compoundssuch as 3-methyl-3-penten-1 -yne and 3,5-dimethyl-3-hexen-1-yne; and by1,3,5,7-tetramethyl- 1,3,5,7-tetravinylcyclotetrasiloxane,1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, andbenzotriazole. The composition preferably contains from 10 to 50,000weight-ppm of the addition-reaction inhibitor.

The present adhesive composition can contain as an optional component anorganic resin powder, metal powder, or inorganic powder, in each casewith an average particle size no greater than 100 μm. Said organic resinpowder can be composed of, for example, a fluororesin or silicone resin;said metal powder can be composed of, for example, silver, nickel, orcopper; and said inorganic powder can be, for example, silica, titaniumoxide, carbon black, alumina, quartz powder, and glass. Moreparticularly, the present adhesive composition containing inorganicpowder with a specific surface area of 50 to 500 m²/g is thixotropic andinhibited from the sedimentation and separation of the previouslydescribed spherical filler. The present adhesive composition can alsocontain, for example, heat stabilizer, flame retardant, colorant, andorganic solvent.

The present adhesive composition can take the form of, for example, arelatively low viscosity fluid, a relatively high viscosity fluid, agrease, or a paste. These forms can be applied using an ejector- orextruder-type device such as a dispenser. In addition, the adhesive canbe applied in a sheet or film configuration by partially crosslinkingthe adhesive or, when the curable polymer composition takes the form ofa hot-melt adhesive, by converting the composition to a sheet or film.

The present adhesive composition preferably cures to give a rubber orgel. The adhesive can be cured at room temperature or by heating. In thecase of heating, it is preferably heated, for example, to 50 to 200° C.using a beating lamp, hot plate, heated block, or forced hot-airconvection oven.

Semiconductor devices according to this invention will now be consideredin detail. The characteristic feature of a semiconductor deviceaccording to this invention is that a semiconductor chip therein isbonded to its chip mounting component by the hereinabove-describedadhesive. The semiconductor device can be, for example, an integratedcircuit, a large scale integrated circuit, or a very large scaleintegrated circuit. Semiconductor devices according to this inventionwill be explained in detail with reference to the drawings appendedherewith. In the semiconductor device shown in FIG. 1, a semiconductorchip 1 is bonded to a semiconductor chip mounting component 2 (a chipcarrier in FIG. 1) by adhesive 3. In this case the semiconductor chip 1is bonded facing the semiconductor chip mounting component 2. Conductors4 are formed on the surface of the semiconductor chip mounting component2 that faces the semiconductor chip 1; these conductors 4 and thesemiconductor chip 1 are electrically connected by leads 5. These leads5 are sealed or packed, in their entirety or partially, by asealant/filler 6. The semiconductor chip mounting component 2 in thesemiconductor device shown in FIG. 1 has been provided with solder balls7 to enable mounting of the semiconductor device on a substrate. Thesemiconductor device in FIG. 1 has also been provided with a frame 8 inorder to protect the semiconductor chip 1 from external mechanicalstresses. This frame 8 is an optional feature for semiconductor devicesaccording to this invention.

In the semiconductor device shown in FIG. 2, a semiconductor chip 1 isbonded to a semiconductor chip mounting component 2 (a circuit substratein FIG. 2) by adhesive 3. In this case, again, the semiconductor chip 1is bonded facing the semiconductor chip mounting component 2. Conductors4 are formed on the surface of the semiconductor chip mounting component2 that faces the semiconductor chip 1; these conductors 4 and thesemiconductor chip 1 are electrically connected by bumps 9. These bumps9 are sealed or packed, in their entirety or partially, by asealant/filler 6. In order to mount the semiconductor device in FIG. 2on a substrate, leads are provided that electrically connect with theconductors 4. Although not shown in FIG. 2, the semiconductor chip 1 maybe sealed with a resin sealant.

Neither the type of semiconductor chip nor the semiconductor chipmounting component are critical for semiconductor devices of thisinvention. The semiconductor chip mounting component can be, forexample, a ceramic-type chip mounting component, for example, alumina orglass; an organic resin-type chip mounting component, for example, epoxyresin, glass fiber-reinforced epoxy resin, polyimide resin, orbismaleimide triazine resin; or a metal-type chip mounting component,for example, stainless steel or copper, and can be, for example, a rigidcircuit substrate or chip carrier or a flexible circuit substrate orchip carrier. The conductors can be formed on the surface or in theinterior of the semiconductor chip mounting component by such means asprinting, vapor deposition, gluing, lamination, and plating. Outerconnecting terminals such as a ball grid (for example, solder balls) orpin grid and other electrical elements or components may also beprovided or mounted. The component that electrically connects thesemiconductor chip with the conductors of the semiconductor chipmounting component can be, for example, bonding wires, leads, or bumps.In order to relax the stresses acting on such components when thesemiconductor device is subjected to thermal shock, in their bondingwire and lead implementations these components are preferably curved orbent and in their bump implementations are preferably made of a materialwith a small Young's modulus.

The use of a sealant/filler is preferred for the purpose of improvingthe reliability of semiconductor devices according to this invention.The sealant/filler can be exemplified by epoxy resin sealant/fillerssuch as epoxy resin sealant/fillers and silicone-modified epoxy resinsealant/fillers; silicone sealant/fillers such as siliconesealant/fillers, epoxy-modified silicone sealant/fillers,acrylic-modified silicone sealant/fillers, and polyimide-modifiedsilicone sealant/fillers; acrylic resin sealant/fillers such as acrylicresin sealant/fillers and silicone-modified acrylic resinsealant/fillers; and polyimide resin sealant/fillers such as polyimideresin sealant/fillers and silicone-modified polyimide resinsealant/fillers. Silicone sealant/fillers are preferred. In order toeffect sealing or packing of the component that electrically connectsthe semiconductor chip with the conductors on/in the corresponding chipmounting component, the sealant/filler is preferably a paste or liquidwith liquids being particularly preferred. With regard to the procedurefor sealing or packing the aforesaid electrically connecting componentwith the sealant/filler, the sealant/filler, for example, can be heatedwith a hot gas current or thermal radiation, or can be brought intocontact with moisture, or can be exposed to ultraviolet radiation or anelectron beam. In the case of semiconductor devices of this invention, apreferred approach for sealing or packing with the sealant/fillercomposition comprises the cure of a thermosetting sealant/filler byheating. This sealant/filler is preferably a sealant/filler that uponthe application of heat thereto forms a cured product that is a gel orrubber at ambient temperature.

The particular process for fabricating semiconductor devices accordingto the present invention is not critical. As an example of a process bywhich the semiconductor device in FIG. 1 can be fabricated, thesemiconductor chip 1 and the semiconductor chip mounting component 2 canfirst be attached together facing each other using the above-describedadhesive; the adhesive can then be cured; and the semiconductor chip 1and the conductors 4 of the semiconductor chip mounting component 2 canthereafter be electrically connected by the leads 5. This electricalconnection can, however, also be effected prior to adhesive cure. Inaddition, these leads 5 can be sealed or packed, in their entirety orpartially, with a sealant/filler and the sealant/filler can then becured. As an example of a process by which the semiconductor device inFIG. 2 can be fabricated, the semiconductor chip 1 and the semiconductorchip mounting component 2 can first be attached together facing eachother using the above-described adhesive; the adhesive can then becured; and the semiconductor chip 1 and the conductors 4 of thesemiconductor chip mounting component 2 can thereafter be electricallyconnected by the bumps 9. Again, this electrical connection can also beeffected prior to adhesive cure. These bumps 9 can also be sealed orpacked, in their entirety or partially, with a sealant/filler and thesealant/filler can then be cured. A frame can be used for the purpose ofpreventing sealant/adhesive outflow during this step. A metal or plasticframe can be used for this purpose, but the frame can also be formedfrom a curable, thixotropic liquid-form or grease-form organic resincomposition. A frame having the form of a rubber or gel is particularlypreferred.

EXAMPLES

The adhesive and semiconductor devices in accordance with the presentinvention are explained in greater detail below through workingexamples. The viscosity values reported in the examples were measured at25° C. using a rotational viscometer (single cylinder geometry,Vismetron V from Shibaura System Co.). The procedure for fabricating thesemiconductor devices and the evaluation methodologies are describedbelow.

Semiconductor Device Fabrication

Semiconductor devices as shown in FIG. 1 were fabricated as follows. Theadhesive was coated on a chip carrier and the semiconductor chip(area=50 mm ) was applied onto the adhesive. The semiconductor chip wasthen bonded onto the chip carrier by curing for 30 minutes at 150° C.while pressing with a hot-press bonder. The semiconductor chip and theconductors formed on the chip carrier were subsequently electricallyconnected by leads. Finally, the leads were completely vacuumimpregnated at 10 torr with a thermosetting silicone sealant/fillerfollowed by cure of the sealant/filler by heating for 30 minutes at 150°C. Twenty semiconductor devices were fabricated by this procedure.

Measurement of the Film Thickness of the Adhesive Layer in theSemiconductor Devices

The average thickness, minimum thickness, and maximum thickness of theadhesive layer were measured on 20 semiconductor devices by subtractingthe thickness of the semiconductor chip and its mounting component (thethickness of the semiconductor chip and its mounting component weremeasured in advance) from the overall thickness of the semiconductordevice.

Measurement of the Spherical Filler Count in the Adhesive Layer of theSemiconductor Devices

The spherical filler particle count per the coated area was determinedby inspecting the adhesive-coated side with a microscope.

Semiconductor Device Reliability Testing

Each semiconductor device was subjected to thermal cycle testing withone cycle consisting of holding for 30 minutes at −55° C. and holdingfor 30 minutes at +150° C. Using the terminals of the conductors on thesemiconductor device, electrical continuity testing was carried outafter 1,000 cycles and after 3,000 cycles. The defect rate wasdetermined from the number of devices that exhibited defectivecontinuity.

Example 1

An adhesive with a viscosity of 13,000 mPa·s was prepared by mixing thefollowing to homogeneity: 100 weight partsdimethylvinylsiloxy-endblocked dimethylpolysiloxane with a viscosity of10,000 mPa·s and a vinyl content,of 0.12 weight %, 3 weight partstrimethylsiloxy-endblocked dimethylsiloxane-methylhydrogensiloxanecopolymer with a viscosity of 20 mPa·s and a silicon-bonded hydrogencontent of 0.7 weight %, 0.5 weight partdimethylhydroxysiloxy-endblocked methylvinylpolysiloxane with aviscosity of 20 mPa·s and a vinyl content of 31 weight %, 0.5 weightpart 3-glycidoxypropyltrimethoxysilane, 0.1 weight part of a 1 weight %isopropanolic chloroplatinic acid solution, 1 weight part of a sphericalsilica micropowder with an average particle size of 160 μm (standarddeviation on the particle size distribution=5 μm) and an aspect ratio of1.1, 0.01 weight part 3-phenyl-1-butyn-3-ol, and 2 weight parts fumedsilica (average particle size=30 μm, BET specific surface area=200 m²/g)whose surface had been treated with hexamethyldisilazane. When heatedfor 30 minutes at 150° C., this adhesive produced a silicone rubber thatgave a value of 20 for the type A durometer specified in JIS K-6253.Semiconductor devices were fabricated using the adhesive, and theresults of evaluation of these semiconductor devices are reported inTable 1.

Comparative Example 1

An adhesive with a viscosity of 12,000 mPa·s was prepared as in Example1, but in this case omitting the spherical silica micropowder (averageparticle size=160 μm, standard deviation on the particle sizedistribution=5 μm, aspect ratio=1.1) that was used in Example 1. Whenheated for 30 minutes at 150° C., this adhesive produced a siliconerubber that gave a value of 20 for the type A durometer specified in JISK-6253. Semiconductor devices were fabricated using the adhesive, andthe results of evaluation of these semiconductor devices are reported inTable 1.

Comparative Example 2

An adhesive with a viscosity of 13,000 mPa·s was prepared as in Example1, but in this case replacing the spherical silica micropowder (averageparticle size=160 μm, standard deviation on the particle sizedistribution=5 μm, aspect ratio=1.1) that was used in Example 1 with anequal amount of silica micropowder that had an average particle size of160 μm, an aspect ratio of 2.0, and a standard deviation on the particlesize distribution of 25 μm. When heated for 30 minutes at 150° C., thisadhesive produced a silicone rubber that gave a value of 20 for the typeA durometer specified in JIS K-6253. Semiconductor devices werefabricated using the adhesive, and the results of evaluation of thesesemiconductor devices are reported in Table 1.

Example 2

An adhesive with a viscosity of 21,000 mPa·s was prepared by mixing 100weight parts of a thermosetting epoxy resin composition with a viscosityof 20,000 mPa·s (TXEP-100 from Dow Corning Toray Silicone Company,Limited, contained 50 weight % spherical silica powder with an averageparticle size of 2 μm and a maximum particle size of 8 μm) tohomogeneity with 1 weight part spherical silica micropowder with anaverage particle size of 160 μm, aspect ratio of 1.05, and standarddeviation on the particle size distribution of 3 μm. When heated for 2hours at 150° C., this adhesive produced a cured epoxy resin that gave avalue in excess of 95 for the type A durometer specified in JIS K-6253.Semiconductor devices were fabricated using the adhesive, and theresults of evaluation of these semiconductor devices are reported inTable 1.

TABLE 1 Com- Com- parative parative Example 1 Example 2 Example 1Example 2 thickness of the adhesive layer (μm) average value 170 171 144181 maximum value 174 174 156 202 minimum value 165 164 112 167spherical filler count  17  16  0  16 semiconductor device defect rate(%) 1,000 cycles  0  0  25  0 3,000 cycles  0  0  60  10

We claim:
 1. An adhesive composition for bonding a semiconductor chip toan attachment member for the chip comprising a curable polymercomposition comprising a spherical filler having an average particlesize from greater than 100 to 1,000 μm and a major axis-to-minor axisratio from 1 to 1.5, and where the standard deviation for the particlesize distribution of the spherical filler does not exceed 10% of theaverage particle size of the spherical filler.
 2. The adhesivecomposition of claim 1, where the content of the spherical filler isfrom 1 weight-ppm to 5 weight % of the curable polymer composition. 3.The adhesive composition of claim 1, where the spherical filler is aninorganic spherical filler.
 4. The adhesive composition of claim 1,where the curable polymer composition is a curable silicone composition.5. The adhesive of claim 1, where the curable polymer composition is acurable epoxy resin composition.
 6. An adhesive compositon according toclaim 1, where the spherical filler has a major axis to minor axis ratiofrom 1.0 to 1.1.
 7. An adhesive compositon according to claim 1, wherethe spherical filler comprises 1 weight-ppm to 2 weight percent of thecurable polymer composition.
 8. An adhesive compositon according toclaim 1, where the spherical filler comprises 1 weight-ppm to 1 weightpercent of the curable polymer composition.
 9. An adhesive compositionaccording to claim 4, where the curable silicone composition is anaddition reaction-cure silicone composition.